Gun firing mechanism with eccentric safety



April 10, 1956 c w. MUSSER GUN FIRING MECHANISM WITH ECCENTRIC SAFETY Filed June 9, 1952 2 Sheets-Sheet 1 68 l FIG. I

INVENTOR. C. WALTON MUSSER BY am, a.

m YJ. J MW xrvonuevs:

April 10, 1956 Filed June 9. 1952 C W. MUSSER GUN FIRING MECHANISM WITH ECCENTRIQ SAFETY 2 Sheets-Sheet 2 53-" 7 54 I I, 84 a1 50 ,4

r r r l n'qq INVENIOR. C.WALTON MUSSER 6 BY We: M, a. M/fiew ATTORNEYS GUN :e- :r r/mcnnrsrsr/r wrrn EccuNrmc sannrr Walton Musser, Mtiiadelphia, Pa.

Application dune 9, 1952, Serial No. 292,6 i2

15 Claims. (Ci. 89-423} (Granted under Titie 35, U. S. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

My invention relates broadly to gun firing mechanisms, and although not limited solely thereto, has particular reference to firing mechanisms used in test guns employed for the purpose of obtaining ballistic data on guns, powder, cartridge components and projectiles. For example, such guns could be advantageously used: (a) to test factors causing gun bore erosion and means for overcoming same; (b) for the accelerated testing of the corrosive properties of various propellant powders on gun components; and (c) for similar testing of the resistance of gun components to those corrosive powders and to erosion caused by a projectile moving rapidly through the gun barrel, as well as many other factors involved in determining the optimum design of firearms and ammunition.

Because of the variety of different purposes for which test guns are used, it is desirable that the firing mechanism for such guns be simply designed and constructed, durable and, of course, safe. For some purposes, it is additionally desirable that means he provided for easily and quickly increasing or decreasing the force applied to the mechanisms firing pin, and for having the movement of the mechanisms hammer control the action of electrical instrumentation associated with the gun.

Before my invention, firing mechanisms for erosion testing guns were built along the lines of firing apparatus used on conventional guns. These prior art firing devices were rather complicated in desi n, relatively fragile, lacked adequate striking force in many instances due primarily to insufficient extent of movement of the mechanisms hammer, and, for these and other reasons, were found unsuited for use on test guns. I have overcome these disadvantages and have introduced concepts new to the art by providing the firing mechanism hereinafter set forth.

To describe my invention briefly, it is constructed upon a breech member which is attached to the rear end of the guns barrel and comprises, in essence, a crankshaft upon whose crankpin a hammer capable of an exceptionally large angular movement is rotatably mounted. The crankshaft, in turn, is mounted upon the breech member and, by means of a trigger lever attached thereto, is rotatable into one of two positions. Rotation of the crankshaft displaces the shafts crankpin in relation to the face of the breech member so that, when the crankshaft is in one position, the hammer is automatically released from rotation-restraining means associated with the firing mechanism, and a preloaded torque spring having considerable rotative force compels the hammer to swing rapidly around the crankshaft and to impinge upon a firing pin which, in usual manner, detonates the ammunition contained in the gun. Additionally, the hammer, by its movement with the crankshaft in this position, completes an electric circuit which controls the action of electrical instrumentation associated with the gun for ballistics recording purposes.

When the crankshaft is in the other position, the hamthe instrumentation.

2,74 l 1% i Patented Apr. 19, 1956 mer, if accidently released, moves rapidly around the crankshaft toward the firing pin with less rotative force, but, because of both the position of the crankpin relative to the face of the breech member and the shape of the hammer, the movement of the hammer is abruptly stopped before the hammer strikes the firing pin and before it completes the electric circuit which controls the action of In this manner accidental detonation of the ammunition is avoided.

A broad object of my invention is to provide a durable, simply designed and constructed firing mechanism for use on guns of the character mentioned.

Another object is to provide a firing mechanism in which accidental discharge of the guns ammunition is prevented.

Yet another object is to provide a firing mechanism in which the hammer is capable of an especially large extent of movement prior to firing the ammunition.

A further object is to provide a firing mechanism which is quickly and easily applicable to any one of numerous types and sizes of test guns.

A still further object is to provide a firing mechanism in which the force applied to the mechanisms firingpin can be quickly and easily increased or decreased.

Still another object isto provide a firing mechanism whose action controls the operation of electrical instrumentation associated with the gun.

The foregoing and other objects and advantages of my invention will become apparent from an inspection of the following description and the accompanying drawings wherein Fig. 1 is an end view of my firing mechanism showing the hammer in its retracted (i. e. awaiting firing) position. For convenience, this figure has been partly broken away and partly sectioned to expose some components which otherwise would not be visible.

line 22 of Fig. 1 showing how the hammer is held in the retracted position. For convenience of drawing, part of the guns barrel and the anterior portion of the ammunition round used in the gun'have been added.

Fig. 3 is a vertical cross-section taken along line 3-3 of Fig. 1 showing some structural details of the mechanism. The part shown in broken line represents a portion of the firing mechanisms trigger lever which has been superimposed to show its position relative to the parts shown in solid line.

Fig. 3A is a vertical cross-section similar to Fig. 3, but showing some parts after having been moved to a different position. Again, a portion of the firing mechanisms trigger lever has been superimposed in broken line to show its position relative to other parts.

Fig. 4 is a vertical cross-section taken along line 44 of Fig. 1. In addition to showing more structural details of my invention, this figure shows how the firing mechanisms hammer, having been accidentally released from the Fig. 2 retracted position, is prevented from striking the mechanisms firing pin. Note the position of the trigger lever, a portion of which has been superimposed in broken line.

. Fig. 4A is a view similar to Fig. 2 but showing how movement of the trigger lever to the position previously indicated in Fig. 3A disengages the hammer from the sear. In Fig. 4A the hammer is fully disengaged from the sear, and is just about to move to the position shown in Fig. 413.

Fig. 4B is a view similar to Fig. 4A, but partly sectioned, and showing how the firing mechanisms hammer impinges upon the mechanisms firing pin during normal operation of the mechanism. Note the position of the trigger lever, a portion of which has been superimposed in broken line, relative to the position shown in Fig. 4.

Fig. 5 is an oblique cross-section taken along line 5-5 of Fig. 4B and showing more structural details of my firing mechanism.

For convenience of description my invention may be considered as comprising the breech assembly 10 (see Figs,

1, 2, 4 and. 4B), and the crankshaft assembly 11 (see Figs;

1 to The essential details of these assemblies follow.

Breech assembly The basic structural component of this assembly is the cylindrical, cup-like breech member 12 .(see'Figs. l, 2

and 4) having a rear end 13 (see Figs. 1 to 5) and a a forward end 14 (see Figs. 2, 4' and 4A). As; shown in Fig. 4, the forward end is internally threaded, and is attached to the rear end 15 of the. guns barrel: 16.1

Axially slidable toward'andaway from=thebarrel s.

rear-end, in. the accommodating, stepped opening 17 in the central portion of the breechv member,.isa firing pin having a shank 13 (see Figs. 1, 2 and 4) and a-some- What larger diametered body 19 (sec Fig. 4). As shown inthelatter figure, the firing pins shank extends beyond;

wardmovement, during operation of my invention,= andx also to provide a durable surface against which-can abut the base end; of an ammunition round dated in the guns bore.

When the firing pin isat its rearwardmost position 2 6 accommo- (see Fig. 4), the pins tip 24 is substantially flushwith the forward surface 27 of the wearplate, and,,whe n the firing pin is at:its forwardmost position (not shown),

the pins tip projects somewhat beyond the wear plates forward surface in order to detonate a percussion primer 28 which forms part of ammunition round 26.

Secured to the breech members rearmost face Ztipbut electrically insulated therefrom, as by an enameled coat ing or other convenient means (not shown), is a contactspring 30 (see Figs. 1, 2, 4 and 4B) which is-fastened in place-by screws 31. As seen in Figs. 2 and 4, the inner end 32 of this spring (i. e. toward the center of'breech member 12) is somewhat removed from the breech members face 20; and the outer end 33 of thespring (i. e. away from the breech members center) containsan electrical socket 34 which is secured in place bymeans of a locknut 35. This socket is electrically" connected to contact spring 30. As shown inFig 4, put 35"and socket'34 extend into,. but do not touch, the. More information concerning contact spring SO'andelectricali socket 34will be given later indisc'ussing the operation accommodating recess 36 formed in the breech.

of my invention.

Located at the breech member's forwardend 14'on a radial line extending 'fromthe' axis of breech is a blind groove 40 (see Fig. 4). Accommodated in'this groove for pivotal-movement toward and away from the breech members rearmost face 20 is a scar 43. having a hooked," This sear is attachedto the breech member by means-of a shoulder outer end 42 ..(see Figs. 2, 4 and 4A).

screw 43 (see Fig. 4) whose body 44 passes through an opening .in thesear, and whose smaller vdiameteredshank 4 5 threads intothe .breechmember. As shown in Fig.14, sear 41 is constantly urged toward the breech. memberfs rearmost faceby means of a coilspring' '46" (see Fig 4), one end of which bears against the sear,

and the other 'end of which bears against the head 47 of.

the shoulder screw.

Additionally,.breechmember 12 is provided with a radially extending arm 4% (seeFigs. l, 2 and 4B) which, during operation of my'invention, aids in threadingand unthreading the breech member from barrel 16,.and with and a trigger lever 53 '(see Figs. -1 to 5).

the radially extending vent hole 49 (see Fig. 4) which extendsbetween the outside-'of the breechmembenand its central, stepped recess 17;

Crankshaft assembly Crankshaft assembly -11 comprises, principally, a crankshaft 50 (see'Figs. l to 5), a'hammer 51 (see Figs. 1, 2, 4 and 5), a torque spring. 52' (see Figs. IIand S), In a manner to be described later, crankshaft assembly 11 is joined to& crankshaft bracket 54 '(seeFigs. l to 5.) which, in

turn, is'secured tobreech member-12;

Crankshaft 50 comprises a journalportion 55 (see Figs. 1 and 5), and an elongated'crankpin portion 56 (see Figs. 1 to 5).

Hammer 51 is a bar-like member having the rearward and forward surfaces 57 and 58, respectively (see Figs.

2, 4, 4A and 4B), which are convenientlyshaped for optimum functioning. This hammer isrotatably mounted upon crankpin 56 which passesthroughone end of thehammer and which is so positioned in the assembly that the-hammeris capable of approximately two hundred.

and seventy degrees (270) rotation aboutthecrankpins axis v(see Figs. 4, 4B and 5).

Torque springSZ, left-hand wound; islocated on pin.56 between journal portion 55 and: the adjacent sideof hammer 51; As {shown in Figs. l andPS, the left end 59 of this spring'is anchored in a recess (more than one of which may be provided), in the crankshafts journal: portion 55, and, as shownin Fig. 5, the right end; 60 of the torque spring is anchored in a similarrecess .(rnore thanone of which may-also in the side ofthe hammer.

Priorto later joining of crankshaft assembly ll -to be provided) formed- -crankshaft bracket 54, torque springSZ may be-wourid up soas constantly to urge hammer 51to rotate upon crankpin 56 in a counterclockwise direction .(as viewed in'Figs. 2, 4; 4A and4B) with the desired'energy;

Adjacent the side of hammer 51 opposite torque spring 52 is a trigger lever 53 (see Figs. 1 to 5). Projecting,

from the inner surface (Le-toward hammer 51), at

one end of the trigger lever is a bearing lug61 (see Figs, 3,13A and 5). groove 62, semi-circular incross section-(see Fig. 5), andhaving bottom portions 63-64 which are substantiallyperpendicular to each other (see Figs. 3 and 3A) Mounted on thetrigger levers bearing lug 61, and

having limited-rotation relative thereto, is. a.plate.65- which, in final assembly, is: joined to the crankshaft brackets rightend 66 (see Figs.- lto 3A, 4A and'5); Passing through this plate are screws 67 and 68 (seeFigs. 1,-3 and3A) which are used to secureplate-65 and the;

ri-ghtyend of crankshaft bracket 54 to'breech' member,

In Figs. 3 and 3A it can be seen .that-1screw67, in: passing through the plate, also passes through L-shaped groove 62, and therebybothlimitsthe' amount. ofrela tive-rotationbetweentrigger lever 53 and plate 65', and

alsoprevents'the trigger lever from being removed, axially, fromthat plate. a a

Asgbest shown in Fig. '5, trigger lever {53 is secured; in-..any convenient-manner, as by a pin 69, to the end of crankpin 56 opposite journal portion 55. Notice-in; that figure and ,alsoin Figs, 3and 3A, that the axisof the crankpin is eccentric to the axis of the trigger levers bearing lug-61.; Actually, the amount ofdisplacement between these axes is the same as thatexisting at the crankshaffls opposite "end. between the crankpin and jo n.

na1 portion:55.- As is usual practice,ibefore trigger lever 53 ispinned-to .crankpin 56, theaxesofjournal portion 55'and bearinglug61 are positioned concentricto each. 7

other.

Crankshafttbracket. 54 consiststof a baseportion, 75

(see 1, 4, ,4B and 5) at theleft, end;- of which 5 )1 Atits; -right.-end: 66,; earlier mentioned; (see-:Fi'gs.

crank-- This lug isiprovided with an L-shaped- 1 to 3A, 4A and 5), the base portion is somewhat reduced in thickness for serving as a bed upon which the crankshaft assemblys plate 65 is attached for rotatably supporting that assemblys right end. Between the left and right ends, base 75 has the beveled sides 78 and 79 (see Figs. 1, 4 and 4B) which are so inclined for functional reasons.

Projecting to the left from the side of upright 77 is an arm 8% (see Figs. 1 and 5). Passing through the upright and extending axially part way into this arm is a blind, spring recess 81 (see Figs. 1, 4, 4B and 5) in the bottom of which is a journal recess 82 (see Figs. 1 and 5). As apparent in Figs. 1 and 5, spring recess 81 and journal recess 82 are eccentric to each other by an amount which permits proper movement of crankpin 56.

Secured in any convenient manner (not shown) to the outer end 83 of arm 80 (see Figs. 1 and 5) is a handle 84 (see Figs. 1, 2, 4, 4B and 5). This handle is so positioned on arm 86 that, when the crankshaft bracket is attached to breech member 12, the axis of the handle parallels the breech members axis, and is substantially the same radial distance from that axis as the center of the spherical knob attached to the breech members radially extending arm 48 (see Fig. 1). Thus, by aid of arm 80 and handle 34, the threading and unthreading of breech member 12 from the guns barrel is further facilitated.

Crankshaft bracket 54 is mounted upon the beveled seat so formed in breech member 12 (see Figs. 2 to 5), and is secured thereto, at its left end, by means of screws 91 (see Fig. 1). At its right end, the crankshaft bracket is secured by means of the earlier-mentioned screws 67 and 63 in a manner later to be described. When mounted upon the breech member, the brackets base portion 75 is substantially diametrically opposed the breech members contact spring 30 (see Fig. 1), and the base portions beveled side 78 is substantially coplanar with the breech members outer surface 2% (see Figs. 4 and 4B).

After crankshaft bracket 54 is attached to breech member 12 by means of screws 91 (see Fig. l), crankshaft assembly 11 is then added to the crankshaft bracket. This is done as follows: The crankshafts journal portion 55 is inserted into journal recess 82 in the brackets arm. At the same time, torque spring 52 is accommodated in the arms spring recess 81. That done, hammer 51 is then adjacent upright 77 (see Figs. 1 and 5).

Plate 65 is then positioned upon right end 66 of the brackets base portion, and screws 67 and 68 (see Figs. 3 and 3A) are passed through the brackets base portion 66 and are threaded into the breech member. However, before adding crankshaft assembly 11 to crankshaft bracket 54, torque spring 52 may be wound up in well-known manner so as forcefully to urge hammer 51 to rotate in a counterclockwise direction (as viewed in Figs. 1, 4, 4A and 4B) upon crankpin 56 with the desired force.

When plate 65 is secured to the crankshaft brackets base portion 66, the trigger levers bearing lug 61 becomes concentric with the arms journal recess 82. Therefore, rotation of crankshaft it) will be about the axis common to those parts, and will cause the axis of crankpin 56 to be moved in usual, well-known manner. Now with crankshaft assembly 11 joined to crankshaft bracket 54, cojoined crankshaft 50 and trigger lever 53 are rotatable to one of two positions: a safe position shown in Figs. 1, 2, 3 and 4, or a firing position shown in Figs. 3A, 4A, 4B and 5; and hammer 51 is rotatable through a large angular extent upon crankpin 56 to any one of three positions: a retracted position shown in Figs. 1, 2, and 4A, a nonfiring, released position shown in Fig. 4, or a firing position shown in Figs. 43 and 5.

The movement of trigger lever 53 and therefore crankshaft 59 to the safe position is limited by bottom portion 63 of L-shaped groove 62 in the trigger levers bearing lug 61 (see Fig. 3). This portion, as shown in Fig. 3, abuts screw 67. The movement of the trigger lever, and therefore the crankshaft, to the firing position is limited by the grooves other bottom portion 64 which abuts screw 67 when the trigger lever is moved to the firing position.

When crankshaft 50 and trigger lever 53 are in the safe position (see Figs. 2, 3 and 4), the perpendicular distance from the breech members rearmost face 20 to the axis of crankpin 56 is less than the perpendicular distance from the hammers forward surface 58 to the crankpins axis. Therefore, the hammers forward surface cannot strike the firing pin if the hammer is released (see Fig. 4).

However, when the crankshaft and the trigger lever are in the firing position (see Figs. 3A, 4A and 4B), the axis of the crankpin is so displaced, relative to outer face of the breech member, that the perpendicular distance from the breech members rearmost face to the crankpins axis is substantially equivalent to the perpendicular distance from the hammer-s forward surface 58 to the axis of the crankpin plus the thickness of contact spring 30. As a consequence of this condition, hammer 51, when released, is able to impinge upon the firing pin (see Fig. 4B) thereby moving it against percussion primer 28 to discharge ammunition round 26 in well-known manner.

Hammer 51 is manually placed in the retracted position by rotating it in a clockwise direction as viewed in Figs. 4 and 4B. This movement of the hammer initially or further winds up torque spring 52, as the case may be, and moves the trigger lever, if in the firing position, back tothe safe position. When fully retracted, the ledge 92 formed on the hammers free end latches under the sears hooked end 42 (see Fig. 2), and is thus held in position until released.

If the latching engagement between the hammer and the sear is accidentally released While crankshaft 50 and trigger lever 53 are in the safe position (see Fig. 4), the hammer, under the action of torque spring 52, moves rapidly toward the firing pin, but, because of the relation between the rearmost face of the breech member and the crankpins axis, the hammer cannot travel far enough to strike the firing pin (also see Fig. 4). This is the nonfiring, released position. Thus accidental firing of the gun is prevented.

Hammer 51 moves from the retracted to the firing" position as a result of moving the trigger lever and the attached crankshaft to the firing position shown in Figs. 3A, 4A and 4B. During this movement, the axis of the crankpin is displaced in relation to the breech members face so that the hammer is pulled free from latching engagement with the sear. Then, under action of the torque spring, the hammer moves rapidly in a counterclockwise direction about crankpin 56 and, because of the relationship between the outer or rear face of the breech member and the crankpins axis, strikes the firing pin (see Fig. 4B) to fire the gun.

Thus, although torque spring 52 constantly tends to move the hammerfrom the retracted position to the two last-named positions, whether or not the hammer assurnes the non-firing, released position or the firing position depends upon the position of the crankpin relative to the rearmost face of the breech member.

Also, it can be noticed that movement of trigger lever 53, by either manual or lanyard operation, from the -safe position (Fig. 4) to the firing position (Fig. 4B), further preloads torque spring 52, thereby imparting additional potential energy thereto. This action increases the total energy deliverable by hammer 51 to the firing pin when the hammer is released from the sears hooked end 42.. in other words, the energy available to fire the primer is the combination of the energies introduced into the torque spring by the optional winding thereof at assembly, by moving hammer 51 to its retracted position and by moving trigger lever 53 to its safe position. This total energy is of greater magnitude when the hammer is released with the trigger lever in the firing position than when the trigger lever is in the safe position. The difference in magnitude is caused by the additional potential nergy, impartedto the torque spring lin movingithe trigger ever from-theisafeto the firingiposition. I

' Operation Having presented the components-of my invention and raving described the essential features thereof, the invenionsope'ration will now. be described Ammunition round 26 is placed. in the: gun barrels rear,

with the rounds base end 25extending somewhat eyond the barrels rear end (see Fig. 4). With the aid f. radially extending arm 48 and the brackets arm 8 3 ire echimember 12 is threadedly attached to therear end t the gun-barreluntil the brcechmembers wear plate 22 toutsvthe base end. of. ammunition round 26withmore or ess pressure, as desired.

Hammer 51 isthenmoved toits retracted position where i t is held by sear 41 (see Fig. 2). As earlier explained, noving the hammer to the retracted positionalso moves hetrigger lever to the-safe position. This-is-accomplished hrough the agency of'the torque spring which, it is aparent,.serves a two-fold purpose. Note at this point, that f the tiring pins tip 24 happened to be projecting beyond :hegsurface of the wear plate, the firing pin would be moved toward therearmosti'ace of the breech until shank. 13 projects therefrom and until the firing pins tip .s substantially fiushwith the wear plates forward sur- 7 Face 27. p

After breech member 12 is attached to gun barrel 16', andhammer $1 retracted, electrical instrumentation 95 (see Fig. 4) to be controlled by the action of hammer 51 isconnected to a convenient source .of electricity by means e'fa connecting plugv 96. Further, an electrical lead 97 is connected for electrical conduction to barrel 16 by the ground connections schematically indicated at 98 and 101, and another lead 99 is connected for electrical conduction to contact spring 39 by means of the leads terminal 100 V tional potential energy to the torque spring, my mecha T nism hasa; dual-safety feature.- Not only will thehammer bei-preventedfrom: striking the firing pin,as explained above; butin-addition, the veryenergy possessed by the hammer upon its accidental release will be far-less than-it has when released after the trigger lever-is in thc firing p s i a-r Fromtheforegoin'g itwill be apparentthatlhave pro: ;vided a durable,;simply designed-and constructedfiriny mechanismathat- I have provided a firing mechanismin p which the accidental discharge-of the guns V ammunition is prevented; that I have provided a firing mechanismi in 1 1 whichthe hammenis capable of an-especially large exwhich .is inserted in the Contact springs electrical socket 34 (see .Fig v4).

When it is desired to fire the gun, trigger lever 53 is moved from the safe position, shown in. Figs. 1 to 3 and 4,: to the firing position shown in Figs. 3A, 4A, 4B and 5.

Assuming hammer 51 to be held in its retracted position by sear 41- (see Fig. 2),.as the trigger lever is moved 1 from the safe position shown in Figs. 2, 3 and 4 toward the firing? position shownin Figs. 3A, 4A and 4B, crankpin 56 is moved away from thesear (from right to left in Fi'g;,2),'and the torque spring is given additional potcntial energy, as earlier explained. This movement of the crankpin pullsthe end ofthe ledge 92 out of engagement with theresiliently mounted sear 41. When the trigger lever reaches the firing position (see Figs; 3A, 4A

and 4B), theharnmer has been moved away from'the sear I by th'eactiorrof the crankshaft until thefhammer is fully disengaged from the sear (see Fig; 4A). At that moment,

torque spring '52 causes the hammer to rotate upon the% crankpin from the position shown'in Fig. 4A to that shown in' Fig.-4B. In moving, the hammer strikes the firing pin and moves it against primer 28 of the ammunition round, thereby firing the gun.

At'th'e time of striking the firing pin, the hammer also meetscontact spring 3%). This action completesan electrical' circuit through instrumentation used to indicate or-record the results ofthe firing.-

If,iby mistake or accident, hammer-51 should be re leased fromsear 41'while trigger lever-Silisin the safeY-J.

position, on. while. the hammer is being moved to itsretracted position, the hammer will promptly: rotate about: crankpin 56 toward the firing pin, but the hammers movement" Willi-be abruptly terminated before it strikes; th'erfiring pin: because the axis of the "crankpin is-not properly'disposed relative to the rear face 20 ofv the breech memben; As a resultythe particular shape of-the merfs forward :surface 58;prevents ifullmovementof the; hammer. which rcomes; *toqrest a safe; distance-from =the;

tent-of movement priorv to firingtheammunition; that-L have provided-a firingamechanism which is quicklyand easily'applicable toany one of numerous types andsizes of test guns that l have provided a firingmechanism in which the force applied to the mechanisms firing pin can be quickly and easily increased or decreased; and that I have provideda firing-mechanism whose action controls the 0p: eration}ofelectricalinstrumentation associated with the Those skilled imthe art will realizethat my invention; can be modified and varied in numerous ways without departingfrom its original-spirit and scope. For that reason I do-not wish-tobelimited in patcnt coverage to the-nar--- row tconfines inhcrent in the illustrativeembodiment of my invention here described, but, rather, only by the metes,

, 'andybounds'of the appended claims.

I claim-: 7

l. A mechanism for=firing percussion-detonatable ammu11ition-;carried by a gun including a breech member re movably-attachable to the guns barrel, a firing pin slidablyaccommodatedinsaid breech member for axial movementgtowardandraway from the-guns barrel, a shaft rotatably-supported-on said breech member, a hammer ro-' tatable' onsaid shaft, acoiled torque spring 'arouhd said shaft,- oneendof said spring being connected to said breech member and the other end of said spring being connected to-said hammer so as-constantly to urge that hammer toward saidfiringapin, restraining means on said breech member for-releasable latching engagementwith said ham-w mersandxfor selectively-holding ,said hammer away from said firing pinaagainst the. force-of said torque spring, anda lever=attached-to saidshaft so that. shaft can be moved rotatively; for the purpose ofincreasing the potential; torque given' said torque spring whereby, upon. release of said restraining; means,- said hammer will be caused by'saidtorque spring to rotateonsaid-shaft to strike said firingpin and thereby' detonate theammuntition carried bytheguns barrel? 2.v In-a mechanism :for firing,percussron-detonatablei.

ammunition-carried -by--a gun and for simultaneouslye rr "ergizinginstrumentation connected to the gun, the com-r bination of a breechmember removably attachable to -the gums barrel, a firingnpin: slidably-accommodated in said breech member-for axial movement toward and away: from, the guns barrel a shaft-rotatably supported on saidg breech member anelectric contact-member carried by 7 said; breech member but electrically insulated therefrom recording instrumentationr electrically connected 10, said;

electrical contact member, a hammer rotatable on said.

shaft so as to strike said firing -;pin and simultaneously;

- said firingpin iandaway from said electrical contact mem.

area-sci her against the force of said torque spring, and a lever attached to said shaft so that shaft can be moved rotatively for the purpose of increasing the potential torque given said torque spring, whereby, upon release of said restraining means, said hammer will be caused by said torque spring to rotate on said shaft to strike said firing pin and detonate the ammunition, and will also be caused simultaneously to abut said electrical contact member so as to complete an electrical circuit connected across said electrical contact and breech members and thereby energize said recording instrumentation.

3. In a mechanism for firing percussion-detonatable ammunition carried by a gun, the combination of a breech member removably attachable to the guns barrel, a firing pin slidably accommodated in said breech member for axial movement toward and away from the guns barrel, a crankshaft mounted on said breech member and selectively rotatable to first and second positions relative to said breech member, a trigger lever secured to the crankshaft for selectively rotating said crankshaft to said first and second positions, and a hammer on the crankpin of said crankshaft, said hammer being displaced relative to said breech member as said crankshaft is rotated so that said hammer is rotatable a sufficient amount on said crankshaft to strike said firing pin and thereby to detonate the ammunition when said crankshaft is in the first position, but so that said hammer is rotatable an insuificient amount and is prevented from striking said firing pin by said breech member when said crankshaft is in the second position.

4. A mechanism for firing percussion-detonatable ammunition carried by a gun, comprising a breech member removably attachable to the guns barrel, a firing pin slidably accommodated in said breech member for axial movement toward and away from the guns barrel, a crankshaft mounted on said breech member and selectively rotatable to first and second positions relative to said breech member, a trigger lever secured to the crankshaft for selectively rotating said crankshaft to said first and second positions, a hammer rotatable on the crankpin of said crankshaft so that said hammer is displaced relative to said breech member as said crankshaft is 1'0- tated, a torque spring connected to said hammer so as constantly to urge that hammer toward said firing pin, and restraining means attached to said breech member for releasable latching engagement with said hammer and for selectively holding said hammer away from said firing pin against the force of said torque spring, whereby when said crankshaft is in the first position said hammer, under influence of said torque spring and upon release of said restraining means will rotate on said crankshaft to strike said firing pin and thereby detonate the ammunition, but will rotate on said crankshaft to strike said breech member and thereby be prevented from striking said firing pin when said crankshaft is in the second position.

5. A mechanism for firing percussion-detonatable ammunition carried by a gun and for simultaneously energizing instrumentation connected to the gun, such mechanism comprising a breech member removably attachable to the guns barrel, a firing pin slidably accommodated in said breech member for axial movement toward and away from the guns barrel, a crankshaft mounted on said breech member and selectively rotatable to first and second positions relative to said breech member, a trigger lever for selectively rotating said crankshaft to said first and second positions, an electrical contact member carried by said breech member but electrically insulated therefrom, recording instrumentation electrically connected to said electrical contact member, a hammer rotatable on the crankpin of said crankshaft so that said hammer is displaced relative to said breech member and relative to said electrical contact as said crankshaft is rotated, a torque spring connected to said hammer so as constantly to urge that hammer toward said firing pin trical contact and breech members and thereby energize said recording instrumentation, but will rotate on said crankshaft to strike said breech member and thereby be,

prevented from striking said firing pin and from abutting said electrical contact member when said crankshaft is in the second position.

6. The combination, in a gun for firing percussiondetonatable ammunition, of a breech member removably attachable to the guns barrel, a firing pin slidably accommodated in said breech member for axial movement toward and away from the guns barrel, a crankshaft mounted on said breech member and selectively rotatable to first and second positions relative to said breech member, a trigger lever for selectively rotating said crankshaft to said first and second positions, an electrical contact member on said breech member but electrically insulated therefrom, recording instrumentation electrically connected to said electrical contact member, a hammer rotatable on the crankpin of said crankshaft, a torque spring on said crankshaft with one end of the spring connected to the crankshaft and with the other end connected to said hammer so as constantly to urge the hammer toward said firing pin and toward said electrical contact member, and a sear mounted on said breech member for holding said hammer away from said firing pin and away from said electrical contact member against the force of said torque spring, whereby when said crankshaft is in the first position the hammer will be released from said scar and will rotate on said crankshaft sutficiently to strike said firing pin and thereby detonate the ammunition, and also simultaneously to abut said electrical contact member so as to complete an electrical circuit connected across said electrical contact and said breech members and thereby energize said recording instrumentation, but said hammer will rotate on said crankshaft and strike said breech member and thereby be prevented from striking said firing pin and from abutting said electrical contact member if said hammer is accidentally released from said sear while said crankshaft is in the second position.

7. The mechanism of claim 3 plus stop means for limiting the rotation of the crankshaft to the first and second position.

8. The combination of claim 6 plus a replaceable wear plate in the breech member for abutting the head end of the ammunition.

9. In a firing mechanism for percussion-detonatable ammunition, the mechanism having a rotatable, eccentric shaft and a hammer rotatably mounted thereon, the combination of: a torque spring for moving the hammer to the firing position, restraining means for holding the hammer in the retracted position against the force of said torque spring, and a trigger lever for rotating the eccentric shaft for the purpose of imparting increased potential torque to said torque spring and for the purpose of simultaneously moving said hammer relative to said restraining means so as to release the hammer from that restraining means.

10. The combination of claim 9 in which the torque spring is on the rotatable, eccentric shaft.

11. The combination of claim 9 in which the restraining means is releasably engageable with the hammer for holding the hammer in the retracted position against the action of the torque spring.

1 1 12, The: combination of tclaim 9 in.- which the trigger ever. is attached to the rotatable, eccentric shaft.

13. In. a firing mechanism forta gun using ;pe'rcus'sion etonatable' ammunition, the combi natitni- .of a breech nemberremovahly attached-to the gun?s'barrel;'a firing; -in slidably accommodated in-csaid breech member anddapted to. fire the ammunition; a crankshaft supported u isaid breech member and selectively. rotatablerelative o thebreech member to two' positions:- a safe :po's'ition nd a firing vposition; va hammer on said crankshafffor" cting :on said firing pin, said harn'mer',wl1en traveling romtavcocked position tolits firing'vpositio'n, being moved na -rectilinear path. byvsaid'fcranlishaftja 'tor'quespr'in-gf '11-? said crankshaft for moving}- said hammer from the iringlpposition-in an arcua'te-path toward said ring; pin; Q-sear en said-breech member .for' releasable engagenent with saidhamm'er to' hold "the hammer in the :ockednposition against the action of sa'idltorque' spring;

lnd a trigger." lever on said crankshaft for'moving that bait to the firing position, so' that theharnme'r carried m the shaft is mov'ed'sub'stantially re'ctilinea'rly from :ngage'ment with said sear into thham'me'rs firing p'osi ion, andpot'entialenergy simultaneouslyis imparted 'to aid torque spring; whereupon said hammer then roat'es'aboutsaid crankshaft under influenceof said torque :p'rihgand'strikeS said firing pin to cause the ammuniion to be fired.

14. The' combination'of 'claim 13 plus stoff'mean's for imiting the rotatability of the crankshaft to its' two posiions.

15 The combination, 'in a mechanisms); firing per} :ussi'on-deto'nat'able ammunition carried-in a gun'and for dmiiltaneously energizinginstrumentation connected to" contact in saidbreech member, but electrically-insulated therefrom; in position to be contacted by' s aidhammei' when theh ammer moves to the firing-lpositionja torque spring on said c'ranks'haft for moving said'hammeif toward the firing 'position" and towardsaid-electrical cont t and.

serving also to" move said crankshaft fi o'mit h'e firing .posi tion to the safe position whenever said hamm er is moved ontof 'the firinglpositio'n, one end of .-said to'rq u e beinganchored in the crankshaft and the other end of that spring being anchored in the hammcrg'a sear yield ably'positio'ned on saidbreechl memberffor releasable engagement withfsaid hammer so as to hold that hammer iii-the cocked position against the forcejof said-torque spring; a trigger lever on said crankshaft for rotating {mat "shaftto its firing positiom thereby impartingtincreased potential energy 'to' said or ue spring; andsimultaneou'sly movingTsaid hammer and wreleasing that hammer from engagement with said seam and electrical:

instrumentation connected across said electrical cent act I and the 'guns' barrel, and-adapted-to be activated when:

said hammer moves to its firing position;- whereby; wh'eni said crankshaft is in the'firingI position, said hammer: will be released from 'said sear and will 'ro'tat'eioii said? crankshaft" sufiicien'tlvfar and with adqu'a'te'Yorc'etd strike said firing pin and therebydeton'ate the ammuni tion', and will also simultaneously 'abut said 'electri'call contact so as to completev an electrical circuit to activate} said'el'ec'tr'ical instrumentation, butsai'd hammer will rotate' on said crankshaft to "strike said breech' memb'eii and he"'gun,'of: a breech member removably attachable to he guns' barrel; a firing pin slidably accommodated -in raid breech member? for axial movement toward and} mayhem the ammunition; a replaceable wear-platein'- iai'd breech member" for abutting the" ammunition;' a

:ranks'haft'mounted on'said breech memberand selec- :ively.rotatable to one of two positions-relativet0"said' Jreech"m'emb'er: 'a' safe'position and a"fir-ingjposition;"

stop'jmeans'to'r limti'ng the rotatability of saidcrank shaft; a hammer rotatable through a large angular expa'nse' on" the crankpin ofsaid crankshaft; an electrical ther'eby be prevented 'fro'm"strikin'g' said firingbin and from abutting said electrical contact if said hamnijer is accidentally released from said sar'while said crankshaft is in the 'safe position; 7

References Cited in the fileof thispate'nt UNlTED S'l Aflli S PATENTS 

